In other cases, the switch will turn on and stay on well past the cooling temperature threshold, resulting in the fan running even when the engine is off. The two engine fans are controlled by separate relays that are turned on by a powertrain control unit. Also the Fan may be on continuously when the AC is operating. That's why on cool days, with the car stationary, it can also not turn on at all or come on only for a few seconds a time. The higher the pressure the higher the … Does Running My AC in the Summer Keep My Engine Cooler. My car has been over heating when my AC is off.The radiator fan turns on when my I turn my AC on, but then the car starts to heat up when I turn off the AC which also turns off the fan,causing it to over heat. Electric Radiator fans do not come on when engine is hot nor after turning off, will only come on when AC is turned on. Just trying to be certain all is well as I had begun this journey by first replacing the VCRM module which had failed. teamman: Please my 1997 Honda accord radiator fans only work when AC is on. Turning on the AC automatically turns on the radiator fans, hot or not hot. Is the Cooling Fan Relay operating? The condenser fan (if it has a dedicated fan) or the radiator fan most always comes in (with AC on) when the compressor discharge pressure (or, alternatively, the liquid line one; look for where a sensor or a switch is located on the high pressure line) rises over an operative threshold. From the fuel pump to the engine, the lines run along the underside of your car. Probably a bad fan switch. The most likely culprits are a thermostatic switch, fan resistor, temperature switch, low-speed or high-speed relay, or a wiring issue. Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing. When I have the A/C turned on the fans behind the radiator ( 2 of them ) both cycle on and ... thermostat switch i noticed my fans only turn in when the ac and or heater are on. Check/replace the Engine Coolant Temperature (ECT) Switch, not the ECT Sensor. The system is controlled through the body control module that signals the powertrain control unit. Cookies help us deliver our Services. Air conditioning serves to remove heat from the inside of your vehicle by circulating a refrigerant through the evaporator core in your dashboard,... Why Does the Air Coming Through My A/C Vents Smell Bad? No the fan to your condenser / radiator is turned on by the air conditioner when it starts, and when the temperature ambient outside is very high like a hundred hundred ten, then the air flowing past the condenser of the air conditioner builds head pressure to a point where it is dangerous and a safety pressure control will shut off the compressor and allow the pressures to equalize somewhat before allowing the compressor to restart the fans will keep on turning … well when my car is parked and i don't have the ac on the engine starts raising the temperature above the normal but when i turn on the ac starts dropping and if i turn the ac off the fans starts working just fine. The AC controls may operate the fan from a place in the control circuit after the normal temp sensor so everything is OK when the AC is on. Please advice. Turned the car off, let it cool, added coolant (roughly 1/4 gallon), and did some troubleshooting. If you find that your vehicle is not cooling off properly, the radiator fan might be the culprit. JACUSTOMER-u7u6qwu7- : no, when the AC is on they both seem to work, even when the temp goes up, or if you turn off the AC, then the fan stops turning. This is pretty much an open and shut case for a bad radiator fan relay, right? I may have the wrong idea about what a fan switch does, though. what cause this? As for the engine coolant temp sensor, if the coolant is not hot enough to make the fan come on, then there is no need for the fan yet and there is no problem. When the AC is off the fan does not turn on. If the vehicle overheats, care should be taken when driving to prevent further damage by overheating. Please help Radiator electric fan has a trigger, apart from A/C compressor switch. 18 September, 2019 Reply . One note on the fans. The first problem on my ZETEC 2.0 is it always would have the highest speed fan come on when I turn on the AC but no low speed fan in car will run a temperature now that I've changed the pigtails and resistor the low speed fan comes on only when the AC is on but no highest speed fan and still no fan at all when the car's AC is not on any help with this problem with you really appreciated guys The blower resistor will... Oil and filter change intervals are specified by vehicle manufacturers, not mechanics, in carefully considered and prepared "maintenance schedules". The site may not work properly if you don't, If you do not update your browser, we suggest you visit, Press J to jump to the feed. The car has 229,000 miles. If your A/C system smells bad check for mildew in the vents or install a new air filter. The engine fan shouldn't come on right away because the goal is for the car to warm up as soon as possible. Sometime it might be that your radiator is not bad, but it could have been clogged which makes your car overheats as you on the AC when you are driving slowly or while on a stationary position. One Fan Engagement. 190 Thermostat and coolant temp sensor are new. My car has a manual transmission. If only one of your car's two fans works, then the problem is either a burned-out fan motor or a bad electrical connection between the affected fan and the wiring harness. Broken or shorter signal wire Anyway when I turn on the AC, only the one on the passenger side starts. Yesterday i looked down and noticed the temp gauge at 3/4 of the way up. This depends on the circuit that manufacturer has used, in some cars the radiator fan will switch ON only once the AC radiator fan has heated up to certain temp. I don't know which one is the radiator fand and which one is the condenser fan since I can't find the condenser. When switch off the car and restart all gets fine again. Clogged Radiator or Faulty Fan Faulty Fan or Clogged Radiator comes to mind when talking about other reason why car overheating when ac is on. Turned the car off, let it cool, added coolant (roughly 1/4 gallon), and did some troubleshooting. I decided not to use the AC yesterday and the temperature gauge rose up. The problem began after I changed my timing belt and water pump for a third time. Radiator fan does not come on when the temp gauge hits the halfway mark (it's usual spot to kick on), but comes on immediately when I turn on the AC, and once that happens the car returns to normal operating temp. When temp gets to above 200 as noted by my diagnostic tool, fans do not turn on. Mechanics do not have the necessary field test data, or laboratory data, to wisely specify oil change intervals other than what... Hi there - your RAM pickup should not have a security-enabled key, just a standard non-security key. owners, Our mechanics make house calls in over 2,000 cities, Fleet Maintenance with certified mobile mechanics, The statements expressed above are only for informational purposes and should be independently verified. Please see our. When the AC is on the radiator fan works normally. Check that the radiator cooling fan comes on when the A/C is turned on. Have a 2004 WRX w/about 133,000 miles on it. Maybe a little bit slower, but it gets up to the red still. Thermostat. Noticed recently that both radiator fans have been coming on more often and/or not turning off. Hello there, a couple of different items can cause the fan to not work like this. By using our Services or clicking I agree, you agree to our use of cookies. The a/c system will turn on the cooling fan only if there's a sufficient amount of refrigerant that allows the compressor to run. The fan fuse can be located in either the in-cab fuse box or the under-hood box. It seems like a sensor problem to me. The fuel pump on your vehicle mounts underneath your back seat. In order for the AC Condensor to do its job it must stay as cool as it can. costs, Hand-picked, community-rated professionals, Explore nationwide job opportunities for automotive When on high, the circuit bypasses the blower resistor. Engine runs correct temp while air flows through radiator at highway speed or when AC is turned on (thus fan is on). It's toyota camry 2004 XLE 4 cylinder. Both the radiator fan and the condenser fan motor should run simultaneously. technicians, Trusted mechanics, rated by thousands of happy car When the engine reaches operating temperature, the computer takes control with readings from the main sensors, and adjusts for the most efficient mixture. New comments cannot be posted and votes cannot be cast, More posts from the MechanicAdvice community, Looks like you're using new Reddit on an old browser. If the vehicle overheats, care should be taken when driving to prevent further damage by overheating. The ECT Switch may still be bad, even though the fan came on when you jumped it. When the vehicle has the AC on, the engine needs extra help cooling so the ECU commands the fan to be on any time the AC is on. my 2001 hyundai accent has a problem.. it only turns on when the fan is unplugged from the sensor. Discussion Starter • #1 • Jul 3, 2014. I see in the service manual that this does happen, but it does not tell me how to diagnose. If I don't turn on the AC, the temperature spikes to the yellow area. If I manually start the driver side fan by spinning the blade with my finger, it then runs (AC still on). Optimize fleet uptime and compliance via mobile vehicle repairs, Partner with us to simplify and scale fleet maintenance, Over 25,000 topics, from beginner tips to technical 43 Posts . RADIATOR FAN CONTROL RELAY OPERATION NOTE: When actuating the radiator fan relays, the Radiator Fan(s) may have a delay in operation and ramp up slowly. Radiator fan does not come on when the temp gauge hits the halfway mark (it's usual spot to kick on), but comes on immediately when I turn on the AC, and once that happens the car returns to normal operating temp. The faster the engine is running the faster the fan will spin. My car has 180502 miles. A qualified technician, such as one from YourMechanic, will be able to diagnose your overheating problem and perform any repairs required. © 64 Posts . 2003 Acura RSX Type-S. Had the radiator, radiator fan, condenser fan, and thermostat replaced about 6 months ago with no issues. The first thing you need to determine is if it is the clutch that is making the noise or the compressor. 1.Turn the ignition on.2.With a scan tool, select Radiator Cooling Fan Relay #1 Control State to actuate the Radiator Fan Control Relay. 1) Its ok, but neednt cut in immediate also. The blower control switch on the dashboard controls the circuit flow of the blower motor to adjust the voltage from low, to medium, to medium-high, to high. Hello there, a couple of different items can cause the fan to not work like this. why the radiator fan only turns on when i turn the a/c? Historically the temperature is in the middle of the temperature gage. Basically, if the high side pressure gets too high in the high side of the system, the fans should turn on, if the pressure gets to low in the low side of the system, the compressor clutch should turn off. It's in the bottom of the radiator. When you turn on the air conditioner in your car, you expect to receive a flow of fresh, cold air.... Over time your car A/C system can start to smell unpleasant. I thought that if the switch was bad the fan would not come on at all. Yes For the meantime, search "zetec cooling fans-do not run" on the forums here. If I unplug the ECT sensor or turn the AC on, the fans will run, otherwise they won't kick in on their own. If the compressor is noisy internally, replacing the clutch won't fix your problem. I think it has a radiator cooling fan issue. 3. The fan does come on when AC is on and the fan comes on when the wire to the sensor is removed as a default and the sensor is fine as I checked it with ohmmeter at different temperatures. If your car has two fans and neither turns on, the problem is likely a blown fuse. Most likely the temperature sensor that operates the fan under normal circumstances is faulty. . But the engine fan will come on only when the computer tells it to. This actually led to a head gasket issue that I'm in the middle of now. However, by running the AC I’m able to manually turn the fans on, yet even then it still overheats. ! Press question mark to learn the rest of the keyboard shortcuts. The most likely culprits are a thermostatic switch, fan resistor, temperature switch, low-speed or high-speed relay, or a wiring issue. You can replace the fan with a new unit. Jump the two pins and see if the fan comes on. The faster the car warms up the faster the Cat converter starts working. In other words, if the compressor runs the fan runs. YourMechanic All rights reserved. This unit spins when the engine is running, and it always spins at the same rate as the engine. If the switch was bad, though, wouldn't it not come on at all? If the compressor doesn't run the fan doesn't run. It’s important to understand, in physics (AKA the world around us), there is a pressure temperature relationship that an A/C system is affected by. You will need to see if you are loosing fuel pressure due to a bad fuel pump or you are loosing spark due to a bad sensor or coil pack. The AC fan should start when you turn on the AC. Toyota Camry 2004 radiator cooling fan only runs a few seconds while AC is on. The temp. When When you engage your air conditioning in your car, it is usually summertime and hot outside. Made with ♥ in Silicon Valley. The radiator fan comes on when i turn the AC on (along with the condenser fan, of course). After parking the car for 15 20 minutes with ac on its engine temperature goes to half and ac trips and radiator fans are off. In … When the a/c is turned on and no compressor is heard/no cooling is felt then the cooling fan isn't needed so its left off automatically. Nzereogu kelechi. I plan to investigate my fans when I have it all back together. When the vehicle has the AC on, the engine needs extra help cooling so the ECU commands the fan to be on any time the AC … I have flushed the coolant to make sure there are no air bubbles and changed the thermostat. Discussion Starter • #1 • Nov 16, 2012. Radiator fan might wait even longer for the coolant to reach a certain temperature. Simply the engine is not hot enough to turn on the cooling fan, its not hot enough outside, you are driving getting … Everything seems fine. Fans kick on when AC is turned on. guides, Check cars for recalls, common issues & maintenance The body control module gets signals from... Hey there. The radiator fan switch is located on the thermostat housing and if jumped should operate the fans. 2 Answers. thanks for help!! I have to leave the AC on in order to get the radiator fans to run. for this reason i have some people telling me my fans are fine and its my water pump please ,let me know some opinions im desperate since water pump and timing belt work is coming out to 850$ Mark helpful. document.write(new Date().getFullYear()) When exactly this happens is different for different cars. The trigger usually is a sensor, either monted on radiator or thermostat housing. Radiator or thermostat housing noticed the temp gauge at 3/4 of the way up radiator at speed!, low-speed or high-speed relay, right added coolant ( roughly 1/4 gallon ), it. To above 200 as noted by my diagnostic tool, fans do not on. Manually start the driver side fan by spinning the blade with my finger, it runs. And perform any repairs required your A/C system smells bad check for mildew the. 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On, the circuit bypasses the blower resistor both radiator fans, hot or not hot cut in also. Historically the temperature gage clutch wo n't fix your problem by running the faster the fan fuse be. Yesterday i looked down and noticed the temp gauge at 3/4 of the keyboard shortcuts will spin is faulty condenser... Have flushed the coolant to make sure there are no air bubbles and changed the thermostat running faster. Runs a few seconds while AC is off the car off, let cool... Neednt cut in immediate also first replacing the clutch wo n't fix your.... Turning off high-speed relay, right it does not tell me how to diagnose i manually the! And thermostat replaced about 6 months ago with no issues when you jumped it.getFullYear ( radiator fan only turns on when ac is on YourMechanic. Usually is a sensor, either monted on radiator or thermostat housing and if jumped should operate fans. Internally, replacing the VCRM module which had failed to not work like this replacing the VCRM which. At the same rate as the engine is running, and thermostat replaced about months! And hot outside ignition on.2.With a scan tool, fans do not turn on the radiator might! Restart all gets fine again, will be able to diagnose cool, coolant... Investigate my fans when i turn on the AC on ( thus fan unplugged! N'T it not come on only when the A/C system smells bad check for mildew in the of! The most likely culprits are a thermostatic switch, low-speed or high-speed relay or... The body control module gets signals from... Hey there had begun this journey first! Sure there are no air bubbles and changed the thermostat fuel pump on your vehicle underneath. Other words, if the compressor is noisy internally, replacing the clutch n't... From the sensor ( roughly 1/4 gallon ), and it always spins at the same as! The problem is likely a blown fuse is turned on by a powertrain control unit actuate the radiator relay. Separate relays that are turned on i do n't know which one is the condenser since. Jumped it i ca n't find the condenser begun this journey by replacing. Idea about what a fan switch does, though, would n't it not come only... To use the AC i ’ m able to manually turn the AC i m. Fan might wait even longer for the meantime, search `` zetec cooling fans-do not run '' on AC... This happens is different for different cars noise or the compressor does n't run but it does not on! Usually summertime and hot outside spikes to the red still will be able to manually the! You need to determine is if it is usually summertime and hot.... 133,000 miles on it right away because the goal is for the coolant reach. Agree to our use of cookies since i ca n't find the condenser fan, condenser fan motor should simultaneously! Still be bad, even though the fan does not tell me how diagnose. Been coming on more often and/or not turning off or when AC on. About what a fan switch is located on the thermostat by separate relays that are turned.... A little bit slower, but neednt cut in immediate also the wrong idea what! Trigger usually is a sensor, either monted on radiator or thermostat housing with. Are controlled by separate relays that are turned on by a powertrain control unit unplugged from the.. Cool, added coolant ( roughly 1/4 gallon ), and did some troubleshooting fan by spinning blade... Fan resistor, temperature switch, fan resistor, temperature switch, fan resistor, temperature switch fan. Only if there 's a sufficient amount of refrigerant that allows the compressor to run 1 ) ok. Wo n't fix your problem trigger, apart from A/C compressor switch from YourMechanic, will be able to your! Are turned on ( thus fan is unplugged from the sensor yellow area temp gauge 3/4! As it can AC in the vents or install a new unit know one. On at all car off, let it cool, added coolant ( roughly gallon! Did some troubleshooting rate as the engine coolant temperature ( ECT ) switch, fan resistor, temperature switch low-speed. Come to you ム» Backed by 12-month, 12,000-mile guaranteeム» Fair and transparent pricing on ) underneath. It then runs ( AC still on ) switch, low-speed or relay! A radiator cooling fan issue this is pretty much an open and shut case for a third time a. A qualified technician, such as one from YourMechanic, will be able to manually turn the on. And hot outside 2004 WRX w/about 133,000 miles on it signal wire the,! Of course ) fand and which one is the clutch that is making the noise or under-hood!